Add default db prefix to getDataConnector function calls (#30)

Add two config options for
* setting which Laravel database connection should be used
* overwriting DataConnector completely with your own custom implementation

Fixes bug where DataConnector was not reading the table-name prefix and passing it on to the Celtic library.

Much appreciation to the contributors and bug-reporters that drove this release.

workon #28

---------

Co-authored-by: Jeroen de Bruijn <jeroen.de.bruijn@brightalley.nl>

config/lti.php

@@ -40,4 +40,27 @@
         ]
     ],
 
+    /*
+    |--------------------------------------------------------------------------
+    | Miscellaneous config
+    |--------------------------------------------------------------------------
+     */
+
+    /*
+        The name of the database connection (in config/databasee.php) which will be used
+        as a data source.  By default, this is the same connection that's your 'default'
+        in config/database.php.
+     */
+
+    // 'connection_name' => 'mysql'
+
+    /*
+        The Celtic LTI library requires a DataConnector class which provides access to the
+        database.  We provide a default implementation of this class which uses the same database
+        that you've configured for your Laravel app.  You can write your own custom class that
+        implements the DataConnectorProvider interface and set it here.
+    */
+
+    // 'data_connector_provider' => LonghornOpen\LaravelCelticLTI\DataConnector\MyCustomDataConnectorProvider::class,
+
 ];

src/Commands/AddLti1p2Platform.php

@@ -6,6 +6,7 @@
 use Exception;
 use Illuminate\Console\Command;
 use Illuminate\Support\Facades\DB;
+use LonghornOpen\LaravelCelticLTI\DataConnector\DataConnectorProviderFactory;
 use LonghornOpen\LaravelCelticLTI\PlatformCreator;
 
 class AddLti1p2Platform extends Command
@@ -41,8 +42,7 @@ public function __construct()
      */
     public function handle()
     {
-        $pdo = DB::connection()->getPdo();
-        $dataConnector = LTI\DataConnector\DataConnector::getDataConnector($pdo, '', 'pdo');
+        $dataConnector = DataConnectorProviderFactory::getDataConnectorProvider()->getDataConnector();
 
         $name = $this->argument('name');
         $consKey = $this->argument('key');

src/Commands/AddLti1p3Platform.php

@@ -6,6 +6,7 @@
 use Exception;
 use Illuminate\Console\Command;
 use Illuminate\Support\Facades\DB;
+use LonghornOpen\LaravelCelticLTI\DataConnector\DataConnectorProviderFactory;
 use LonghornOpen\LaravelCelticLTI\PlatformCreator;
 
 class AddLti1p3Platform extends Command
@@ -56,8 +57,7 @@ public function handle()
             return 0;
         }
 
-        $pdo = DB::connection()->getPdo();
-        $dataConnector = LTI\DataConnector\DataConnector::getDataConnector($pdo, '', 'pdo');
+        $dataConnector = DataConnectorProviderFactory::getDataConnectorProvider()->getDataConnector();
         $deployment_id = $this->option('deployment_id');
         $client_id = $this->option('client_id');
 

src/DataConnector/DataConnectorProvider.php

@@ -0,0 +1,7 @@
+<?php
+
+namespace LonghornOpen\LaravelCelticLTI\DataConnector;
+
+interface DataConnectorProvider {
+    public function getDataConnector();
+}

src/DataConnector/DataConnectorProviderFactory.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace LonghornOpen\LaravelCelticLTI\DataConnector;
+
+class DataConnectorProviderFactory {
+    public static function getDataConnectorProvider()
+    {
+        $dc_class = config('lti.data_connector_provider', LaravelDataConnectorProvider::class);
+        return new $dc_class();
+    }
+}

src/DataConnector/LaravelDataConnectorProvider.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace LonghornOpen\LaravelCelticLTI\DataConnector;
+
+use ceLTIc\LTI\DataConnector\DataConnector;
+use Illuminate\Support\Facades\DB;
+use LonghornOpen\LaravelCelticLTI\DataConnector\DataConnectorProvider;
+
+class LaravelDataConnectorProvider implements DataConnectorProvider
+{
+    public function getDataConnector()
+    {
+        $connection_name = config('lti.connection_name', config('database.default'));
+        return $this->getDataConnectorForConnection($connection_name);
+    }
+
+    public function getDataConnectorForConnection($connection_name)
+    {
+        $pdo = DB::connection($connection_name)->getPdo();
+        $dbTableNamePrefix = config('database.connections.' . $connection_name . '.prefix', '');
+        return DataConnector::getDataConnector($pdo, $dbTableNamePrefix, 'pdo');
+    }
+}

src/LtiServiceProvider.php

@@ -7,6 +7,7 @@
 use LonghornOpen\LaravelCelticLTI\Commands\AddLti1p2Platform;
 use LonghornOpen\LaravelCelticLTI\Commands\AddLti1p3Platform;
 use LonghornOpen\LaravelCelticLTI\Commands\UpdateConsumerSetting;
+use LonghornOpen\LaravelCelticLTI\DataConnector\DataConnectorProviderFactory;
 
 class LtiServiceProvider extends ServiceProvider
 {
@@ -27,7 +28,8 @@ public function boot() : void
         ]);
 
         try {
-            Tool::$defaultTool = LtiTool::getLtiTool();
+            $dataConnector = DataConnectorProviderFactory::getDataConnectorProvider()->getDataConnector();
+            Tool::$defaultTool = LtiTool::getLtiTool($dataConnector);
         } catch (\PDOException $e) {
             // LtiTool tries to connect to the DB.  Can't do that?
             // Not worth stopping boot() for...any real DB connection

src/LtiTool.php

@@ -10,6 +10,7 @@
 use ceLTIc\LTI\ResourceLink;
 use ceLTIc\LTI\UserResult;
 use Illuminate\Support\Facades\DB;
+use LonghornOpen\LaravelCelticLTI\DataConnector\DataConnectorProviderFactory;
 
 class LtiTool extends LTI\Tool
 {
@@ -31,12 +32,14 @@ public static function getLtiTool($dataConnector = null) {
     }
 
     // Generally, you shouldn't construct this object yourself; use the
-    // singleton provided by LtiTool::getLtiTool() instead.
+    // singleton provided by LtiTool::getLtiTool() instead.  Celtic's
+    // LTI code processes LTI nonces (one-time-use tokens) and invalidates
+    // them after processing, so creating a second LtiTool in the middle
+    // of a request will often fail due to nonce problems.
     public function __construct($dataConnector = null)
     {
         if ($dataConnector === null) {
-            $pdo = DB::connection()->getPdo();
-            $dataConnector = DataConnector::getDataConnector($pdo, '', 'pdo');
+            $dataConnector = DataConnectorProviderFactory::getDataConnectorProvider()->getDataConnector();
         }
         parent::__construct($dataConnector);